Many consumer packaging applications employ reclosable polymeric packages, such as reclosable bags. These bags may employ a resealable closure for sealing products within the bags. For example, a zipper-type resealable closure may include male and female profiles extending along the length of the zipper. A male profile, typically tree-shaped with an expanded head portion supported by a narrower trunk portion, is typically disposed opposite a mating female profile that is adapted to mate with the male profile by a pair of legs having locking edges or cornered shoulders. These profiles are interlocked by properly aligning the male and female profiles and pressing them together along the length of the zipper. The opposing legs of the female profile slide over the expanded head portion of the male, thereby interlocking the female profile to the head of the male profile via the cornered shoulders and resting in the trunk portion.
The interlocking fit of the male and female profiles must fulfill at least two competing requirements in that the interconnection between the male and female profiles should be snug enough to impede passage of gases and liquids therethrough, but the fit also must be substantially loose to allow ease of separation of the male and female profiles by a consumer (e.g., using typical hand opening forces). These competing requirements are generally required to be consistenyl satisfied over a broad range of service temperatures and during the entire life of the package. Thus, despite the snug fit generally provided by such resealable closures, gases (e.g., air), and sometimes liquids, may nonetheless flow into and/or out of the reclosable polymeric packages via gaps between the male and female profiles of the resealable closure. This flow is undesired in various instances, such as when food product is stored within the package, or when it is desirable to maintain a vacuum within the package.